Photographic developer



P 6, 1958 H. ULRICH EI'AL 2,852,374

PHOTOGRAPHIC DEVELOPER Filed March 16, 1955 log J-t &

INVENTORS.

HANS ULRICH, RUDOLF MERSCH, OTTMAR WAHL, DETLEF DELFS.

2 A TTORNE Y:

United States Patent 6 PHOTOGRAPHIC DEVELOPER Hans Ulrich, Koln-Stammheim, Rudolf Mersch, Leverkuseu-Bayerwerk, and Ottlnar Wahl and Deflef Delfs, Gpladen, Germany, assignors to AGFA Aktiengesellschaft fiir Photofabrikation, Leverkusen, Germany, a corporation of Germany Application March 16, 1955, Serial No. 494,687 Claims priority, application Germany March 18, 1954 11 Claims. (Cl. 96-66) The present invention relates to photographic silver halide developing substances and especially to such substances which are derived from l-phenyl-3-amino-pyrazolines.

1-phenyl-3-amino-pyrazoline has only a very slight activity as a photographic developer, so that it is of no practical value. The same also applies for its sulpho acid or carboxylic acid derivatives which are readily soluble in alkali. Moreover, the substitution of the aryl radical by aliphatic substituents does not provide any substantial change as regards the developing power.

It has. now. been found that 1-aryl-3-amino-pyrazolines, which contain OH or NH groups as substituents in the aryl radical in the 4-position are highly active developers with very valuable photographic properties, it being possible for the hydrogen atoms of the NH group to be replaced by organic radicals as for instance by alkyl, oxalkyl, sulpho-alkyl or carboxy-alkyl groups. If necessary, the aryl radical may also carry other substituents apart from OH or NH groups, such as alkyl' groups and halogen atoms.

Such compounds are not only very rapidly acting photographic developers when used alone in alkaline solution, but they show super-additive effects to a degree not hitherto known, particularly in combination with known types of silver halide developing substances, such as pyrocatech'ol, pyrogallol', hydroquinone, p-aminophenol, oaminopl'ienol, oand p-aminophenols substituted in the aromatic nucleus of in the amino group, such as p-methylaminophenol and N-p-oxyphenyl'glycin, 2.4-diaminophenol, oand p-pheriylendiarnin and derivatives thereof. As an additive to less active developers, they have such astrong activating eifect even in minimum amounts that completely novel effects may be produced. As isknown, the combinations of hydroquinone and p-methylaminophenol-are the standard developers which are most commonly used because of their valuable properties. If the p-methylaminophenol in such standard developers is replaced by a few percent by weight of the novel compounds, not only is it possible to obtain development effects which are comparable to the hydroquinone-p-methylaminophenol developer, but there may additionally be produced substantially more advantageous effects. Such developers, for example, become operative more quickly, they provide higher threshold values and steeper gradation with deeper blackening. The special action of the developer substances is also obtained, if they are present for instance in developing solutions which are used for developing silver halide layers, which contain known developing substances. Furthermore the developing substances according to the present invention may be incorporated into silver halide layers by themselves or in combi-nation with other known developing substances, whereafter these layers are developed either in alkaline aqueous solution or in alkaline aqueous solution containing developing substances.

Despite the very small amount which is used as compared with p-methylaminophenol, for example l to 2,852,374 Patented Sept. 16, 1958 2 of the usual p-methylaminophenol quantities, such developers are of high strength, inthat an almost complete regeneration of the activator takes place by exchange action withthe hydroquinone, so that itis pos-- sible to refer to a catalytic action of the novel compounds.

These developer mixtures are, therefore, characterizedby being particularly inexpensive. Furthermore, it is possible therewith to produce special developers for a wide variety of purposes in' the photographic art.

The said l-aryl-3-aminopyrazolines may be obtained'by the processes disclosed in British patent specification l lo H2. I

In the following examples, the parts which are indicated are parts by Weight:

Example 1 A grey step wedge (factor f: {/5) is exposed on normal silver chloride paper (Agfa Lupex) of normal gradationon a sensitometer. The development is carried out at 20 C. in solutions of the following composition:

Water Hydroquinone Na-sulphite anhyd. Soda anhyd Potassium bromide. p methylaminophenol l-(p-hydroxyphenyl) -3amiuopyrazoime l-phenyl-S-hydroxypyrazoline. 1-phenyl-3-aminopyrazoline The first image traces appear with Developer A after 11 seconds. Developer B after 11 seconds Developer C after 15 seconds Developer D after 35 seconds Developer E after 50 seconds Developer F after 50 seconds After one minute, the development is stopped by a 2% acetic acid bath and fixed in the normal manner. A comparison of the points shows the following:

As compared with Developer A Developer B shows one grey stepmore, Developer C shows one grey step less, 7 Developer D shows eight grey steps more, Developer E shows only a flat image trace, Developer F shows only aflat image trace.

Developer B, therefore, gives the deepest blackening.

Example 2 Grey step wedges are exposed as in Example 1 on silver chloride or silver .bromide papers and developed in developers of the following composition:

Water 1, 000 1, 000 1, 000 Hydroquinone 6 6 6 NazSO; anhyd 40 40 40 Nanoos 811136 11- 4O 10 40 B1 1.5 1.5 1.5 p-Methylaminoph 2. 5 l-(p-hydroxyphenyl)-3-arninopyraz0line 0. 125 l-phenyl-3-hydroxypyrazoline 0. 125

Using a silver chloride paper, the first traces of the image appear with Developer A after 6 seconds, Developer B after 6 seconds, Developer C after 8 seconds,

and when using the silver bromide paper, with Developer A after 13 seconds, Developer B after seconds, Developer C after 15 seconds.

After one minute, the development is stopped. The great rapidity of developer B is expressed in an advance of 1 /2 grey steps as compared with A and C.

If the developers A, B and C are previously exhausted in similar manner by development of 3 square metres of silver bromide paper per litre of developer, then 2 to 3 grey steps more are visible with developer B than with developers A and C.

This ratio is not changed in any way if the developer is subjected to the action of air in such manner that a moderate current of air is drawn in for twenty hours in gas-washing bottles.

In all cases developer B shows the deepest blackening.

Example 3 A grey step wedge (factor f=2) is exposed on the technical photographic silver halide film Agfa-Printon R on a sensitometer. Each is developed for four minutes at 19 C. in the developers of the following composition:

Water NB: S O s anhyd. Hydro quinone K 0 KBr p-Methylaminophenol 5 l-(p-hydroxyphenyD-B-ammopyrazoline 1- (p-acetaminzr phenyD-3-aminopyravnl in p l-(p-N-methylacetaminophenyl)-3-aminopyrum] in n From the diagram shown in the accompanying drawing it is readily possible to read off the sequence of the developers as regards their activity. It increases from the developer Pin the sequence F, E, D, B, A, C.

Example 4 4 Example 5 In a developer A for silver chloride and silver bromide papers, of the following composition:

p-Methylaminophenol-sulphate grams 2.5 Sodium sulfite do 40 Hydroquinone do 6 Potassium carbonate do 40 Potassium bromide do 2 Benzotriazole do 0.03 Water ml 1000 the p-methylaminophenol-sulfate is replaced by 0.125 gram of l-(p-methylaminophenyl)-3-amino-pyrazolinedihydrochloride or 0.132 gram of l-(p-ethylaminophenyl)-3-amino-pyrazoline-dihydrochloride (developer B). A third developer C contains only an equimolecular amount, i. e. 0.082 gram, of p-rnethylaminophenol.

Prints are produced from a negative and developed in the aforesaid developers. The printing process using the developer B takes only of the time of exposure required by developer A. Moreover, development of the image with developer B proceeds at higher velocity than with developer A. The advance in time is about 15%. Developer C works slowly and yields only a flat trace of an image.

The l-(p-methylaminophenyl) 3 amino-pyrazoline is obtained by refluxing 23.2 grams of l-(p-acetmethylaminophenyl)-3-aminoyrazoline (freezing point P. P. 263 C.) with 270 ml. of 10% aqueous sodium hydroxide solution for 10 hours and cooling the reaction mass, whereby the first mentioned compound crystallizes. It is transformed into the hydrochloride according to customary methods. The 1-(p-ethylaminophenyl)-3-aminopyrazoline is produced by the same method from l-(pacetethylaminophenyl)-3-aminopyrazoline. (F. P. about C. under decomposition.)

Example 6 In a developer A for silver chloride and silver bromide papers, of the following composition:

the p-methylaminophenol-sulfate is replaced by 0.20 gram of the free base 1-(p-aminophenyl)-3-arnino-pyrazoline or by 0.28 gram of the corresponding dihydrochloride (=developer B). The developer B is more stable to oxidation by air and of higher capacity than developer A. Thus, for instance a solution containing a given amount of developer B is exhausted by developing 10 m? of a silver chloride paper, whereas 6 m. of the same paper suifice to exhaust the same amount of developer A. 1- (p-arninophenyl)3-amino-pyrazoline isproduced by refluxing 21.8 grams of l-(p-acetaminophenyl)-3-aminopyrazoline (F. P. 204 C.) with 220 ml. of 5% aqueous sodium hydroxide solution for 6 hours and thereafter cooling the reaction mass. There are obtained crystals which melt at about C. under decomposition.

Example 7 In a hard working developer A of the following composition the p-methylaminophenol is replaced by 0.10 gram of the free base 1(p-aminophenyl) -3-aminopyrazoline or 0.14 .gram of the corresponding dihydrochloride (=developer B). Developer B applied for instance to the photographicfilm 'AgfaPrinton K gives a harder gradation than developer A and is of higher capacity.

Example 8 A highly active developer A for X-ray films has the composition In comparison with this developer A, developer B contains, instead of p-methylaminophenol, only 0.09 gram of l-(p-aminophenyl)-3-amino-pyrazoline or 0.095 gram of l-(p-amino-m-methylphenyl)-3-amino-pyrazoline. A comparison of the developing process with Agfa X-ray film shows that developer B has a greater capacity than developer A. The 1(p-amino-m-methylphenyl)-3-aminopyrazoline is obtained by refluxing 23.2 grams of 1-(4'- acetylamino-3'-methylphenyl)-3-arninopyrazoline (F. P. 237 C.) with 230 ml. of 10% aqueous sodium hydroxide solution for 12 hours and thereafter cooling the reaction mass. The crystals formed melt at 166 C. under decomposition.

What we claim is:

1. A photographic developing agent which consists essentially of 1-aryl-3-aminopyrazoline, wherein the aryl group is substituted in the 4-position by a radical selected from the group consisting of OH and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl, in admixture with a silver halide developing substance comprising a benzene derivative having at least two sub stituents in the benzene nucleus, said substituents being selected from the group consisting of hydroxy and amino groups and being attached to the benzene nucleus at a position selected from the group consisting of the 1.4 and the 1.2 positions.

2. A photographic developing agent consisting essentially of an alkaline solution of hydroquinone and 1- aryl-3-aminopyrazoline, wherein the aryl group is substituted in the 4-position by a radical selected from the group consisting of H and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl.

3. The developing agent of claim 5 wherein the proportion, by weight, between the hydroquinone and the 1-aryl-3-aminopyrazoline is between about 135 to 1 and about 30 to 1.

4. A developing agent consisting essentially of l-paminophenyl-3-aminopyrazoline and hydroquinone.

5. A developing agent consisting essentially of 1-p-hydroxyphenyl-3-aminopyrazoline and hydroquinone.

6. A silver halide layer in which is incorporated a developing agent consisting essentially of 1-aryl-3-aminopyrazoline wherein the aryl group is substituted in the -position by a radical selected from the group consisting 'ofOH and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl.

7. A silver halide layer in which is incorporated a developing agent consisting essentially of 1-aryl-3-aminopyrazoline, wherein the aryl group is substituted in the 4-position by a radical selected from the group consisting of OH and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl, in admixture with a silver halide developing substance comprising a benzene derivative having at least two subsituents in the benzene nucleus, said substituents being selected from the group consisting of hydroxy and amino groups and being attached to the benzene nucleus at a position selected from the group consisting of the 1.4 and the 1.2 positions.

8. A silver halide layer in which is incorporated a developing agent consisting essentially of hydroquinone and 1-aryl-3-aminopyrazoline wherein the aryl group is substituted in the 4-position by a radical selected from the group consisting of OH and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl.

9. The process of developing photographic silver halide layers which comprises treating the silver halide layers with a developing agent consisting essentially of an alkaline solution of l-aryl-3-aminopyrazoline wherein the aryl group is substituted in the 4-position by a radical selected from the group consisting of OH and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl.

10. The process of developing photographic silver halide layers which comprises treating the silver halide layers with a developing agent consisting essentially of l-aryl-3-aminopyrazoline wherein the aryl group is substituted in the 4-position by a radical selected from the group consisting of OH and wherein R and R are members of the group consisting of hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl in admixture with a silver halide developing substance comprising a benzene derivative having at least two substituents in the benzene nucleus, said substituents being selected from the group consisting of hydroxy and amino groups and being attached to the benzene nucleus at a position selected from the group consisting of the 1.4 and the 1.2 positions.

11. The process of developing photographic silver halide layers which comprises treating the silver halide layers with a developing agent consisting essentially of an alkaline solution of hydroquinone and 1-aryl-3-amin0- wherein R and R are members of the group consisting of pyrazoline wherein the aryl group is substituted in the hydrogen, alkyl, oxalkyl, sulfoalkyl, and carboxyalkyl.

4-position by a radical selected from the group consisting of OH and I References Cited in the file of this patent 5 FOREIGN PATENTS N/ 679,678 Great Britain Sept. 24, 1952 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,852,374 September 16, 1958 Hans Ulrich et al,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below,

In the grant, lines 3 to 5, for eussignors to AGFA Aktiengesellschaft iiir Photofabrikation, of Leverkusen, Germany, a corporation of Germany," read assignors to AGFA Aktiengesellschaft, of Leverkusen, Germany, a corporation of Germany, line 14 for "AGEA Aktiengesellschaft fur Photofabrikation, its successors" read AGFA Aktiengesellschaft, its successors in the heading to the printed specification, lines 5 to '7, for "assignors to AGFA Aktiengesellschaft fu'r Photofabrikation, Leverkusen, Germany, a corporation of Germany" read assignorsto AGFA Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany column 5, line 17, Example 8, for

Sodium carbonate 60 read Sodium carbonate 40 Signed and sealed this 13th day of January 1959 (SEAL) Attest:

KARL AXLINE ROBERT C, WATSON Attesting Officer Commissioner of Patents 

10. THE PROCESS OF DEVELOPING PHOTOGRAPHIC SILVER HALIDE LAYERS WHICH COMPRISES TREATING THE SILVER HALIDE LAYERS WITH A DEVELOPING AGENT CONSISTING ESSENTIALLY OF 1-ARYL-3-AMINOPYRAZOLINE WHEREIN THE ARYL GROUP IS SUBSTITUTED IN THE 4-POSITION BY A RADICAL SELECTED FROM THE GROUP CONSISTING OF OH AND 